I have correctly installed the Plex integration in home assistant, but I cannot show Plex the files in an ssd disk inserted in the raspberry usb socket.
In fact, when I try to create a new library in plex I can’t find the directory of the ssd disk: it only sees the root of the microSD card.
How do you recognize a disk or a usb stick attached to the raspberry?
Do I need to modify some configuration files with the editor somehow? 
There’s a Plex NAS addon that should do what you want.